1. Field of the Invention
The present invention relates to a mounting apparatus for a photoelectric converting device and a fabrication method thereof so as to accomplish a micro camera.
2. Description of the Related Art
In recent years, in the fields of medical machinery and industrial robotics that use micro cameras, needs for reducing the size and weight of such cameras are becoming strong. To satisfy such needs, a mounting apparatus of which an photoelectric converting device is wire-bonded and packaged with ceramics has been developed. As another example, a small mounting apparatus of which a CCD is directly disposed on a wiring board has been developed.
FIG. 9 shows a mounting apparatus disclosed as Japanese Patent Laid-Open Application No. Hei 7-99214. In this mounting apparatus, a CCD that is an photoelectric converting device is directly disposed on a substrate. The mounting apparatus is fabricated in the following fabrication steps. Copper leads 91b are formed on an insulation sheet 91a formed on a wiring board 91 (at step 1). An optical glass 92, an ultraviolet ray thermosetting type adhesive agent 93, and so forth are layered (at steps 2 and 3). Next, an anisotropic conductive paste 95 is coated on the copper leads 91b connected to the CCD 96 on the wiring board 91 (at step 4). The CCD 96 has gold bumps 96b. Electrode portions 96a and the gold bumps 96b of the CCD 96 are thermally fitted and thereby connected (at step 5).
As shown in FIG. 10, the CCD 96 connected to the wiring board 91 is housed in a housing 104 along with a signal processing board 101, a camera cable 102, a lens portion 103, and so forth. As a result, the fabrication of the micro camera is completed.
However, in such a conventional mounting apparatus for an photoelectric converting device, when the optical glass 92 and the wiring board 91 are adhered, foreign matter and protrusion of an adhesive agent take place and they adversely affect the picture quality of the photoelectric converting device.
In the mounting apparatus shown in FIG. 9, the optical glass 92 and the CCD 96 are very closely disposed so as to reduce the size of the camera. When a micro camera is used for a medical machine or the like, an optical lens with a wide angle and a large depth of focus is used. Thus, when a foreign matter 97 and a protrusion 93a of an adhesive agent 93 are present on the optical glass 92, they are imaged by the CCD 96 and displayed on a TV screen.
At step 3 shown in FIG. 9, when the foreign matter 97 stuck on the optical glass 92 is removed by a cotton rod 121 as shown in FIG. 12A, the foreign matter is dispersed in the vicinity of the wiring board 91. In addition, since it is very difficult to strictly control the coating condition of the adhesive agent, the protrusion of the adhesive agent deteriorates the yield.
Foreign matter takes place at the cutting surface of the wiring board 91 and the cutting surface of the optical glass 92. In addition, foreign matter is generated by humans. In a 1/4-inch 400,000-pixel type CCD, the size of each pixel is as small as 5 .mu.m. On the other hand, the size of foreign matter that can be found in the fabrication process is at most 50 .mu.m. Thus, it is very difficult to control foreign matter smaller than 5 .mu.m.